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Date: Sat, 18 Jun 2011 22:28:12 +0400
From: Vasiliy Kulikov <segoon@...nwall.com>
To: kernel-hardening@...ts.openwall.com
Subject: Re: proc info restrictions problem
Solar,
On Sat, Jun 18, 2011 at 14:42 +0400, Vasiliy Kulikov wrote:
> I feel doubt whether ptrace_may_access() may be changed to something
> more simple. Both -ow and -grsecurity use changed posix permissions and
> gid on procfs files, so maybe just match subject's euid vs. object's uid?
Another choise - remove hidepid=2 at all. As proc connector uses struct
proc_event as an information send to listeners, hidepid=1 is not related
to proc connector:
http://lxr.free-electrons.com/source/include/linux/cn_proc.h?a=avr32#L45
It means that with hidepid=1 only procfs and taskstats should be
restricted. Taskstats uses direct "unicast" information sending, so
ptrace_task_may_access_current() and ptrace_may_access() should work
(with a patch I've recently sent to lsm list as RFC).
It is sad that hidepid=2 is losen and processes may spy on other users'
processes, but I don't see any technical solution for hidepid=2 and
cn_proc problem.
Thanks,
--
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
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